For
either
memory map format and
either
type
of
addressing,
the
contents
of
register
Ru
1
are:
MEMORY MAP LOADING PROCESS
The
initial
map image address (in
register
R)
is
the
virtual
address
of
the
first word
of
the
memory map control
image.
The
initial
count,
as
contained
in
register
Ru1
specifies
the
word length
of
the
control image
to
be
loaded.
A word
count
of
64
(for
8-bit
format)
or
128 (for
11-bit
format) is
sufficient
to
load
an
entire
block
of
256 memory map
con-
trol registers. The memory map control registers
are
treated
as a
circular
set,
with
the
first
register
following
the
last;
thus,
a word
count
greater
than
64
(8-bit
format)
or
128
(ll-bit
format) causes
the
first registers to be
overwritten.
The
initial
value
of
the
control
start
field
of
register
Ru1
points
to
the
first
page
(512 words)
of
virtual
addresses
that
are
to be
controlled
by
the
memory map control image being
loaded.
The memory map control image
is
loaded
into
the
memory map control registers
one
word
at
a
time.
As
the
contents
of
each
word
are
loaded into
either
two
orfour
mem-
ory map control
registers,
the
map image address
is
incre-
mented by 1,
the
word
count
is
decremented
by 1,
and
the
value
in
the
control
start
field
is
incremented
either
byfour
(if
the
memory map control image
is
in
the
8-bit
format)
or
by two (if
the
memory map control image
is
in
the
11-bit
format). The loading process
continues
until
the
word
count
is
reduced
to
zero.
When
the
load process
is
completed,
the
map image address
of
register
R
contains
a
value
equal
to
the
sum
of
the
initial
map image address plus
the
initial
word
count,
the
word
count
of
register
Ru1
has a
value
of
zero,
and
the
control
start
field of
register
Ru1
contains
a
value
equal
to
the
sum
of
the
initial
contents
plus four
or
two times
the
initial
word
count.
LOADING
THE
ACCESS
PROTECTION
CONTROLS
CONTROL
IMAGE
Each
access
protection
control image word
contains
sixteen
2-bit
fields;
or,
the
access
protection
codes for
16
consecu-
tive
pages
of
virtual
memory. Thus,
the
access
protection
control image for 128K word (256 page)
virtual
memory
is
contained
within
16
contiguous memory
locations,
desig-
nated
as
the
access
protection
control image
area.
The format
of
a typi ca I
access
protection
control image
word is:
The instruction format for loading
the
access
protection
code is:
Depending upon
the
type
of
addressing,
the
format
of
reg-
ister R
contents
is
one
of
the
following:
IfMA=O;
Ac cess Prote
ion
If
MA
= 1
and
MM =
0;
For
either
type
of
addressing,
the
contents
of
register
Ru1
are:
ACCESS PROTECTION LOADING PROCESS
The
initial
access
protection
control image address
in
reg-
ister R
is
the
virtual
address
of
the
first word
of
the
access
protection
control image.
The
initial
count
in
register
Ru1
specifies
the
word
length
of
thp
rnnt
..
nl
;rn,.,,.,p
tn
h.,
In,.,r1.,r1 A
\A/1"\",..1
,..""n+
"j:
11..
:
....
"j:-
----
-----.-
• •
"--.;;;J-
--
--
.---
.....
-_.
~
-
••
-.-
--_
•••
_
•.•
-
........
-.
fi
cient
to
load
the
entire
block
of
256
access
protection
con-
trol registers. The
access
protection
control registers
are
treated
as
a
circular
set,
with
the
first
register
following
the
last;
thus,
a word
count
greater
than
16
causes
the
first-reg-
isters loaded
to
be
overwritten.
The
initial
value
of
the
control
start
field
of
register
Ru
1
points
to
the
first
page
(512 words)
of
virtual addresses
that
are
to
be
controlled
by
the
access
protection
control image
being
loaded.
The
access
protection
control image
is
loaded
into
the
access
control registers
one
word
at
a
time,
..
thus
loading
the
control registers for
16
consecutive
pages with
the
contents
of
each
image word. As
each
image word is
loaded,
the
access
protection
control
imag~
address
is
incremented
by 1,
the
word
count
is
decremented
by 1,
and
the
value
in
the
control
start
field
is
incremented
by
4.
The
lo~ding
process
continues
until
the
word
count
is
reduced
to
O.
When
the
loading process is
completed,
the
parameters
con-
tained
within
registers
Rand
Ru1
have
the
following values:
Access
protection
control image address =
initial
access
protection
control
image address plus
the
initial
word
count.
Count
=
O.
Control Start =
initial
contents
plus 4 times
the
initial
word
count.
Control Instructions 115
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